diff --git a/REST-API.md b/REST-API.md
index 323c4ec..9fc4c05 100644
--- a/REST-API.md
+++ b/REST-API.md
@@ -92,6 +92,8 @@ curl http://localhost:3000/users/login \
 
 THIS WORKS !! Alternatively, look at api.py example at https://github.com/wekan/wekan
 
+NOTE: Username and password is case sensitive. So type BIG and small letters correctly.
+
 ```bash
 curl -H "Content-type:application/json" \
       http://localhost:3000/users/login \